1. Technical Field
The present invention relates to a fluid transmission flat-face coupler with frontal annular seal.
Fittings which may be rapidly coupled to one another to connect a fluid feed, by means of rigid pipes or flexible hoses, are frequently required for fluid transmission for example in operating machines and hydraulic equipment
2. Description of the Related Art
The known quick coupling fittings usually consist of two couplings, named male and female, which are fastened to respective pipes to be joined and which can be coupled together by screwing or by snapping.
The aforesaid male and female couplers are formed by fixed parts and axially sliding parts, which at rest are arranged in a closing position of a fluid passage gap and during the coupling between two members are displaced by engaging with corresponding parts of the other member to an opening position of said passage gap.
The currently marketed fluid transmission solutions show that the coupling between the male coupler and the female coupler is not always very easy with effort increasing incrementally as the residual pressure present in the circuit increases.
Italian patent application MI2012A001254 by the present Applicant concerns a fluid transmission coupling connectable with constant effort provided with a pressure compensation and relief system which is complex and not very cost-effective. Said known fitting further comprises a central locking system which is mechanically cumbersome and ineffective in some situations of accidental actuating by the user.
U.S. Pat. No. 4,540,021 describes a fluid transmission fitting with a female coupler, which includes a frontal seal, which prevents the introduction of impurities only when coupled to a male coupler and during the step of coupling or uncoupling of the male coupler. A closing plug is provided to prevent the introduction of impurities into the uncoupled female coupler.
U.S. Pat. No. 3,407,847 describes a fluid transmission fitting with a female coupler, which includes a frontal seal, which prevents the introduction of impurities only when coupled to a male coupler and during the step of coupling or uncoupling of the male coupler. Said frontal seal does not cover the wide frontal opening of the female coupler when the female coupler is uncoupled, the impurities thus being disadvantageously able to enter.
It is the object of the present invention to make a pipe fitting, in which the effort required for the coupling operation is minimum and independent from the residual pressure present in the circuit.
It is a further object of the present invention to make the fitting mechanically simpler and allow a suitable hydraulic control to guarantee user safety also in the event of accidental actuation.
It is a yet further object to prevent the introduction of impurities into the female coupler both if it is uncoupled from the male coupler and if it is coupled to the male coupler and during the step of coupling or uncoupling with or from the male coupler.
According to the present invention, such objects are reached by means of a fluid transmission flat face fitting as described in claim 1.